In the early history of the oil and gas industry, the first sources of petroleum were reservoirs that naturally seeped to the earth's surface. In the course of coal mining operations in the 1850s, the existence of underground reservoirs of petroleum were discovered. These new reservoirs were easily accessible by simple drilling techniques, and the oil and gas extracted either by pumping, or free flowing to the surface by virtue of pressure within the reservoir itself.
Early oil reservoirs were generally close to the surface. With the development of modern geological sciences, it became apparent that oil and gas reservoirs existed deep within the earth's crust, and at multiple locations around the world.
More recently a variety of techniques have been developed to improve the ability to obtain oil and gas from geological formations that have been traditionally difficult to extract from. These include such formations as shales and other similar formations that contain large quantities of oil and gas that are trapped within the rock itself.
One technique that has been developed is the process of hydraulic fracturing, or “fracking.” In this process, a wellbore is first drilled into an oil and gas containing formation. At regions within the target formation, the wellbore is perforated, and then high-pressure liquid injected into the well. The liquid can exit the wellbore through the perforations and enter the surrounding oil and gas formation. With sufficient hydraulic pressure, the rock in the formation is literally fractured, resulting in release of oil and gas into the spaces produced by the fracturing process. In order to improve the efficiency of the fracturing process, the fracturing liquid, typically water, may also contain one or more proppants such as sand or ceramics that function to keep the fracture open.
One of the limitations of current fracking technology is that is requires the use of significant quantities of water, which ultimately is then extracted from the wellbore as hydrocarbon contaminated waste water. Because of the potential for damage to the environment, contaminated fracking fluid is a challenging problem for the oil and gas industry. In addition, fracking operations may be limited, or even impossible, in areas without sufficient water supplies.
Thus, it would be an advantage to have a fracking tool that can produce the necessary disruption in an oil and gas formation to release otherwise unextractable hydrocarbons. It would also be an advantage to provide a tool that is able to fracture such formations while using substantially less fracturing fluid than is normally used using prior art tools and methods.